Position measurement system employing total transmitted flux quantization

Abstract

A device for measuring the position (location and orientation) in the six degrees of freedom of a receiving antenna with respect to a transmitting antenna utilizing transmitter charge quantization. The transmitting component consists of a transmitting antenna of known location. The transmitting antenna is driven by a pulsed excitation. The receiving antenna measures the transmitted magnetic field. A computer then provides the correct position and orientation output.

1 . Magnetic position measurement system comprising:
 a) a magnetic transmitter connected to a charge source, said source causing a net cumulative electric charge to flow through said transmitter over an interval of time, said transmitter producing a transmitted net magnetic flux time integral;   b) a sensor outputting a sensed value proportional to said transmitted net magnetic flux time integral over said interval of time;   c) a processor operating on said sensed value from said sensor and outputting values of position and orientation for said sensor relative to said transmitter.   
   
   
       2 . The system of  claim 1 , wherein said net cumulative electric charge is measured by sensing and integrating, as a function of time, current flowing through said transmitter. 
   
   
       3 . The system of  claim 1 , wherein said net cumulative electric charge is pre-measured and stored in a capacitor, said capacitor discharging into said transmitter in such a manner as to produce a non-zero net cumulative electric charge value through said transmitter. 
   
   
       4 . The system of  claim 2 , wherein said transmitter possesses a non-linear current-to-transmitted-field transfer function, non-linear properties of said transfer function being corrected by a correction coefficient. 
   
   
       5 . The system of  claim 1 , further including a double integrator, determination of said transmitted net magnetic flux time integral being carried out by double integrating output of a fixed coil disposed in a vicinity of said transmitter. 
   
   
       6 . The system of  claim 1 , wherein said transmitter possesses a non-linear current-to-transmitted-field transfer function. 
   
   
       7 . The system of  claim 1 , further including an integrator, determination of said transmitted net magnetic flux time integral being carried out by integrating output of a fixed DC responsive magnetic sensor disposed in a vicinity of said transmitter. 
   
   
       8 . The system of  claim 1 , wherein said charge source produces current waveforms having non-zero steady state intervals. 
   
   
       9 . The system of  claim 1 , wherein said charge source produces current waveforms devoid of non-zero steady state intervals. 
   
   
       10 . The system of  claim 1 , wherein said sensor is responsive to a time derivative of a magnetic field from a coil followed in series by a double integrator. 
   
   
       11 . The system of  claim 1 , wherein said sensor is responsive to steady state magnetic fields, such as one chosen from the group consisting of a fluxgate magnetometer, hall effect sensor, magnetoresistive sensor, magneto-optical sensor, followed by an integrator. 
   
   
       12 . The system of  claim 11 , wherein said integrator includes an A/D converter and a digital accumulator. 
   
   
       13 . The system of  claim 11 , wherein said integrator comprises an analog integrator followed by a sampling mechanism. 
   
   
       14 . The system of  claim 1 , wherein said source produces waveforms having characteristics chosen from the group consisting of triangular, exponential, partial sinusoid, and trapezoidal amplitude vs. time. 
   
   
       15 . A magnetic position measurement system employing:
 a) a magnetic transmitter connected to a driver, said driver causing a net cumulative electric charge to flow through the transmitter over a first interval of time, said first interval ending with a steady state interval;   b) a sensor outputting a sensed value proportional to said net cumulative electric charge through said transmitter over said first interval of time, said sensed value being sampled at an end of said steady state interval;   c) a processor which operates on said sensed value and outputting values of position and orientation for said sensor relative to said transmitter.   
   
   
       16 . The system of  claim 15 , wherein no net current charge passes through said transmitter during said steady state interval. 
   
   
       17 . The system of  claim 15 , further including a second interval of time, said sensed value comprising a first sensed value, said sensor outputting a second sensed value proportional to said net cumulative electric charge through said transmitter over said second interval of time. 
   
   
       18 . The system of  claim 17 , wherein said second interval of time is equal to said first interval of time, and said second sensed value is subtracted from said first sensed value. 
   
   
       19 . The system of  claim 17 , wherein said driver causes a second net cumulative electric charge to flow through said transmitter during said second interval of time, said second interval ending with a steady state interval, and said second net cumulative electric charge flowing through said transmitter in a negative direction with respect to said first electric charge. 
   
   
       20 . The system of  claim 15 , wherein said sensor is responsive to a time derivative of a magnetic field from a coil, followed in series by a double integrator. 
   
   
       21 . The system of  claim 15 , wherein said sensor means comprises a sensor responsive to steady state magnetic fields, such as one chosen from the group consisting of a fluxgate magnetometer, hall effect sensor, magnetoresistive sensor, magneto-optical sensor, followed by an integrator. 
   
   
       22 . The system of  claim 15 , wherein said integrator includes an A/D converter and a digital accumulator. 
   
   
       23 . The system of  claim 15 , wherein said integrator comprises an analog integrator followed by a sampling mechanism. 
   
   
       24 . The system of  claim 15 , wherein said driver produces waveforms having characteristics chosen from the group consisting of triangular, exponential, partial sinusoid, and trapezoidal amplitude vs. time. 
   
   
       25 . A magnetic position measurement system employing:
 a) a magnetic transmitter connected to a driver, said driver causing a net cumulative electric charge to flow through the transmitter over an interval of time, said net cumulative electric charge comprising a series of sequential charge pulses;   b) a sensor outputting a sensed value proportional to said net cumulative electric charge through said transmitter over said interval of time;   c) a processor operating on said sensed value from said sensor to output values of position and orientation for said sensor relative to said transmitter means.   
   
   
       26 . The system of  claim 25 , wherein a number of said sequential charge pulses is varied as a function of said sensed value. 
   
   
       27 . The system of  claim 25 , wherein a number of said sequential charge pulses is varied as a function of sensor signal-to-noise ratio. 
   
   
       28 . The system of  claim 25 , wherein a number of said sequential charge pulses is varied as a function of environmental eddy current settling time.